POS0924 USEFULNESS OF LOW-DOSE CT IN PSORIASIS AND PSORIATIC ARTHRITIS PATIENTS WITH NON-SPECIFIC AXIAL SYMPTOMS
Authors: S. A. Germe, G. Ayan, S. Dogan, B. Yalici-Armagan, L. Kiliç, U. Kalyoncu
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Low-dose CT (ldCT) has been shown advantegous over conventional radiography (CR) in showing spinal structural changes in Axial Spondyloarthritis (AxSpA) [1,2]. There is no data on the value of ldCT in psoriatic arthritis (PsA) patients. <h3>Objectives</h3> The aim of this study is to determine the contribution of spinal ldCT to the diagnosis and disease severity in patients with psoriasis (PsO) and PsA with non-spesific axial symptoms. <h3>Methods</h3> 143 PsO patients referred from the Dermatology Outpatient Clinic in the last 9 months were evaluated; patients with any axial symptoms (116) were included. 47 of 116 patients (40.5%) had ldCT. Patients were evaluated with pelvis CR, lumbar/cervical CR and whole spinal ldCT. Age, gender, PsO and PsA disease duration were recorded. Patients were divided into four groups according to CR findings; 1. Modified New York criteria (mNY) not met, 2. Only sacroiliitis (SI) according to mNY, 3. SI and syndesmophyte (SIN) present, 4. Only SIN (according to the consensus of two rheumatologists UK and LK). All spinal CTs (coronal and sagittal planes) were evaluated by two rheumatologists. Syndesmophytes were determined between C2-S1 and it was also noted if bridging was present (according to the consensus of two rheumatologists UK and GA). The contribution of spinal ldCT to axial involvement was evaluated. <h3>Results</h3> 47 patients (n=15 (32%) with inflammatory, n=32 (68%) non-specific axial symptoms) were evaluated in this study. The mean age of the patients (68.1% female, 31.9% male) was 47.4 years. Median duration of PsO was 15 years. Median disease duration of 10 patients with a previous diagnosis of PsA was 4.5 years. 12 (25.5%) patients had only PsO and 35 (74.5%) patients had PsA. 25/35 (71%) of those with PsA had axial involvement (SI and/or SIN) according to CR, CR was normal in 10/35 (29%) patients (Figure 1). When the whole spinal ldCT was evaluated, SIN was detected in 8/12 (66.7%) of patients with only PsO (8 thoracic, 4 lumbar, 2 cervical). On the other hand, 30/35 (85.7%) of PsA patients had SIN (Figure 1). The distribution of SIN in ldCT is shown in Table 1. Bridging SIN and Andersson lesion were detected in 1/12 (8.3%) and 2/12 (16.7%) of PsO patients versus 17/35 (48.6%) and 8/35 (22.9%) of PsA patients, respectively. In 15/22 (68%) of those with normal CR, 7/9 (77.7%) of those with only SI in CR, 5/5 (100%) of those with SI and SIN in CR, 11/11 (100%) of those with only SIN in CR were found to have syndesmophyte on ldCT. Accordingly, 38/47 (80.8%) patients had at least one syndesmophyte on ldCT (Table 1). <h3>Conclusion</h3> When PsO and PsA patients with non-specific axial symptoms were evaluated with spinal ldCT, new syndesmophytes were found in a significant proportion of patients (2/3 of patients with only PsO), additionally an increased distribution of syndesmophytes was observed. The thoracic vertebra is one of the most frequently involved area in psoriatic disease similar with SpA. Comparative studies with a healthy control group are needed to determine the potential role of ldCT. <h3>References</h3> [1]De Bruin, F. et al. Ann. Rheum Dis 2018; 77:371–377. [2]De Koning A et al.Ann Rheum Dis 2018; 77:293–299 <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.